[PATCH 2/2] iomap: Use folio_copy_tail()

["Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>]

The iomap handling of tails doesn't support multi-page folios, so
convert it to call folio_copy_tail(), which does.

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
 fs/iomap/buffered-io.c | 23 ++++++-----------------
 1 file changed, 6 insertions(+), 17 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 10a203515583..d08edf2de19c 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -215,31 +215,20 @@ static int iomap_read_inline_data(const struct iomap_iter *iter,
 {
 	struct iomap_page *iop;
 	const struct iomap *iomap = iomap_iter_srcmap(iter);
-	size_t size = i_size_read(iter->inode) - iomap->offset;
-	size_t poff = offset_in_page(iomap->offset);
-	size_t offset = offset_in_folio(folio, iomap->offset);
-	void *addr;
+	loff_t pos = iomap->offset;
 
 	if (folio_test_uptodate(folio))
 		return 0;
 
-	if (WARN_ON_ONCE(size > PAGE_SIZE - poff))
-		return -EIO;
-	if (WARN_ON_ONCE(size > PAGE_SIZE -
-			 offset_in_page(iomap->inline_data)))
-		return -EIO;
-	if (WARN_ON_ONCE(size > iomap->length))
-		return -EIO;
-	if (offset > 0)
+	if (pos > folio_pos(folio))
 		iop = iomap_page_create(iter->inode, folio, iter->flags);
 	else
 		iop = to_iomap_page(folio);
 
-	addr = kmap_local_folio(folio, offset);
-	memcpy(addr, iomap->inline_data, size);
-	memset(addr + size, 0, PAGE_SIZE - poff - size);
-	kunmap_local(addr);
-	iomap_set_range_uptodate(folio, iop, offset, PAGE_SIZE - poff);
+	folio_copy_tail(folio, pos, iomap->inline_data,
+			iomap->length);
+	iomap_set_range_uptodate(folio, iop, pos - folio_pos(folio),
+			folio_size(folio) - offset_in_folio(folio, pos));
 	return 0;
 }
 
-- 
2.39.1